This is a conversation between me and my then 2yo (can't remember what I had done to offend her):
dd: I don't love you, I don't want you for a mummy.
me: That doesn't matter because I love you and I will always be your mummy.
dd: Not when I'm grown up!
me: Yes, even when you're grown up. You may move away from home, you may go and live in a house of your own, but I will still be your mummy and I will still love you.
dd (with enormous emphasis): No! YOU'LL BE DEAD THEN!
This was 20 years ago, dd and I are very close, and I have absolutely no intention of kicking the bucket.
Her 2yo verbal development was simply far more advanced than her emotional development, she had no idea what being dead really meant or how she would feel if something happened to me. She just said something that sounded very impressive to her, and I reassured her that I could handle the situation and that there was no risk that my love or my grown-up ability to deal with her would wobble.
Her emotional development has caught up since. 